U.S. patent application number 10/817958 was filed with the patent office on 2005-02-10 for method for the restoration of damaged areal components.
Invention is credited to Mielke, Rainer.
Application Number | 20050029235 10/817958 |
Document ID | / |
Family ID | 32864471 |
Filed Date | 2005-02-10 |
United States Patent
Application |
20050029235 |
Kind Code |
A1 |
Mielke, Rainer |
February 10, 2005 |
Method for the restoration of damaged areal components
Abstract
Repair of compressor blades (6) of aircraft engines is performed
by build-up welding against an essentially horizontal backing (8)
whose surface shape is the exact negative of the respective bottom
side of the blade to be repaired. With low rework effort, the
blades of blisks can, in the installed state, be repaired or fully
restored at any point with high quality upon removal of the damaged
portion.
Inventors: |
Mielke, Rainer; (Oberursel,
DE) |
Correspondence
Address: |
Davidson Berquist Klima & Jackson, LLP
4501 North Fairfax Drive, Suite 920
Arlington
VA
22203
US
|
Family ID: |
32864471 |
Appl. No.: |
10/817958 |
Filed: |
April 6, 2004 |
Current U.S.
Class: |
219/121.64 |
Current CPC
Class: |
F05D 2230/30 20130101;
F05D 2230/232 20130101; F01D 5/34 20130101; Y10T 29/49318 20150115;
B23K 26/342 20151001; B23P 6/007 20130101; F05D 2230/80 20130101;
F01D 5/005 20130101 |
Class at
Publication: |
219/121.64 |
International
Class: |
B23K 026/34 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 12, 2003 |
DE |
DE 103 16 966.0 |
Claims
What is claimed is:
1. A method for the restoration of damaged blades of gas turbines
by build-up welding, in which a material is melted, in a form and
length to be restored and in subsequent layers, on and along a
sectional cut at which a damaged blade portion was separated,
wherein the build-up welding is performed against an essentially
horizontal backing which form-fits a remaining blade surface and
whose surface shape is substantially a negative of a side of the
blade facing the backing at least in the portion to be
restored.
2. A method in accordance with claim 1, wherein at least two weld
layers are applied on top of one another, in correspondence with
the thickness of the blade.
3. A method in accordance with claim 2, wherein build-up welding is
performed at least one of co-directionally and contra-directionally
parallel to the sectional cut.
4. A method in accordance with claim 2, wherein build-up welding is
performed at least one of co-directionally and contra-directionally
vertical to the sectional cut.
5. A method in accordance with claim 4, wherein protective-gas
build-up welding is performed by laser powder welding
technology.
6. A method in accordance with claim 5, wherein weld material is
supplied from at least one of a side and circularly.
7. A method in accordance with claim 6, wherein a size and shape of
the blade to be restored, as well as the transition geometry, are
determined by imaging methods, and the travels for the deposition
of the weld layers are calculated and controlled by computer.
8. A method in accordance with claim 7, wherein the welding process
is performed on one of a one-stage or multi-stage compressor blisk
in the installed state.
9. A method in accordance with claim 8, wherein the restored blade
is subject to surface processing and thermal treatment.
10. A method in accordance with claim 1, wherein build-up welding
is performed at least one of co-directionally and
contra-directionally parallel to the sectional cut.
11. A method in accordance with claim 1, wherein build-up welding
is performed at least one of co-directionally and
contra-directionally vertical to the sectional cut.
12. A method in accordance with claim 1, wherein protective-gas
build-up welding is performed by laser powder welding
technology.
13. A method in accordance with claim 12, wherein weld material is
supplied from at least one of a side and circularly.
14. A method in accordance with claim 1, wherein a size and shape
of the blade to be restored, as well as the transition geometry,
are determined by imaging methods, and the travels for the
deposition of the weld layers are calculated and controlled by
computer.
15. A method in accordance with claim 1, wherein the welding
process is performed on one of a one-stage or multi-stage
compressor blisk in the installed state.
16. A method in accordance with claim 1, wherein the restored blade
is subject to surface processing and thermal treatment.
17. An apparatus for the restoration of damaged blades of gas
turbines by build-up welding, in which a material is melted, in a
form and length to be restored and in subsequent layers, on and
along a sectional cut at which a damaged blade portion was
separated, comprising a welding cavity which includes a welding
cavity bottom and side walls and is temporarily attachable to a
bottom side of the blade to be repaired and removable downwards
after repair welding, with a surface shape of the welding cavity
bottom being a substantially identical negative of a surface shape
of a side of the blade to be repaired, and with an inner contour of
the side walls substantially matching a contour of a leading edge
and a trailing edge of the blade to be repaired.
18. An apparatus in accordance with claim 17, wherein the welding
cavity is constructed of a heat-resistant, heat-dissipating
material.
19. An apparatus in accordance with claim 18, wherein heat
conductivity of the material is selected such that a locally
limited weld pool and slow cooling of the weld pool is ensured.
20. A method for the restoration of a damaged three dimensional
component of a gas turbine by build-up welding, in which a material
is melted, in a form and length to be restored and in subsequent
layers, on and along a sectional cut at which a damaged component
portion was separated, wherein the build-up welding is performed
against an essentially horizontal backing which form-fits a
remaining component surface and whose surface shape is
substantially a negative of a side of the component facing the
backing at least in the portion to be restored.
Description
[0001] This application claims priority to German Patent
Application DE10316966.0 filed Apr. 12, 2003, the entirety of which
is incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a method for the restoration of
worn or otherwise damaged components by build-up welding, in
particular, solid, three-dimensional compressor blades of aircraft
engines.
[0003] The compressor blades of aircraft engines are subject to
considerable erosion in the area of the tip and--if the content of
sand in the air is high--also in the area from the tip to the
trailing edge. In addition, the leading edge of the compressor
blades, in particular, is prone to damage by larger objects (by
small stones, for example). Damaged or worn blades can be replaced
by new ones if they are separately manufactured and detachably
mounted to the compressor disk. This already costly method can,
however, not be applied to compressor wheels made in blisk
technology where the disk forms an integral part with the
blades.
[0004] In fact, the possibilities for the repair of the compressor
blades are limited. Here, laser powder build-up welding presents
itself as one of the few prospects, in particular under the aspect
that a mold supporting the weld pool conformally contains the tip
area to be restored, allowing the rework effort to be kept low in
comparison with free build-up welding. Laser powder build-up
welding in a mold is, however, disadvantageous in that the blade
can only be restored in a confined tip area of a few millimeters,
this being due to recesses limiting the depth of input of the laser
beam and the powder in the mold and, further, the complex,
three-dimensional blade shape impeding the removal of a longer mold
from the repaired blade upon build-up welding.
BRIEF SUMMARY OF THE INVENTION
[0005] In a broad aspect, the present invention provides a method
and an apparatus for the repair of worn or damaged solid compressor
blades, in particular, blisk-technology compressor blades, by
build-up welding enabling three-dimensionally shaped blades to be
restored on each edge and in any required length with low rework
effort.
[0006] It is a particular object of the present invention to
provide solution to the above problems by a method and by an
apparatus for the performance of this method in accordance with the
features described herein. Further advantageous embodiments of the
present invention will become apparent from the description
below.
[0007] The principal idea of the invention is that the restoration
of the damaged component portion by build-up welding is performed
directly on an essentially horizontal backing whose surface shape
is the exact negative of the bottom side of the respective
component or component portion. The surface of the backing
form-fits the bottom side of the component portion to be restored
or the remaining component portion, respectively.
[0008] Since the backing, which is temporarily attached to the
bottom side of the remaining compressor blade portion, can be
removed downwards after repair welding, even three-dimensionally
shaped compressor blades can be repaired or fully restored at any
point. Welding is executable, in high quality, in the technically
advantageous gravity position, even on compressor blisks in the
installed state, with weld layers being depositable
cross-sectionally on top of one another in accordance with the
respective blade thickness.
[0009] Build-up welding is performed co-directionally or
contra-directionally parallel with or vertical to a sectional plane
at which the damaged portion was separated from the component.
[0010] In accordance with a further feature of the present
invention, the component portion to be restored is determined by
imaging methods, with the movements of the laser beam (13a) and of
the powder feed nozzle (14) being calculated, and the welding
process exactly controlled, on this basis.
[0011] The apparatus according to the present invention comprises a
welding cavity, with a cavity bottom forming the backing whose
inner surface is the negative of the respective blade side, and
with side walls whose inner contour corresponds to the counter of
the leading or trailing edge of the blade to be repaired.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The present invention is more fully described in the light
of the accompanying drawings showing a preferred embodiment. In the
drawings,
[0013] FIG. 1 is a partial view of a two-stage compressor wheel
made in blisk technology on which blade repair, in accordance with
the present invention, is performed in horizontal gravity position
by laser powder build-up welding,
[0014] FIG. 2 is a detail of FIG. 1 in which a compressor blade to
be restored is placed in a welding cavity,
[0015] FIG. 3 is a side view of compressor blade in which the area
separated due to wear or damage is indicated by the respective
dotted lines from which the compressor blade is restored by
build-up welding,
[0016] FIG. 4 is a side view of a compressor blade whose repair is
performed by contour-parallel contra-directional build-up welding
along the separated side of the compressor blade,
[0017] FIG. 5 is a side view of a compressor blade on which
build-up welding is performed contra-directionally and essentially
vertically to the separated side of the compressor blade, and
[0018] FIG. 6 is a side view of a compressor blade on which
build-up welding is performed co-directionally on the separated
side of the compressor blade.
DETAILED DESCRIPTION OF THE INVENTION
[0019] In accordance with FIG. 3, the following primary cases of
blade damage and restoration apply:
[0020] 1. The blade is unusable over its entire length and will,
therefore, be separated at the blade root along line 1 and restored
from this sectional plane.
[0021] 2. The blade is deformed at the leading edge. The damaged
portion will be separated along line 2 and the blade restored from
this sectional plane.
[0022] 3. The tip of the blade is, as usual, eroded by the effect
of flow and will be repaired by build-up welding from line 3.
[0023] 4. The blade is worn in a corner area at the tip and
trailing edge by an exceptionally high content of airborne
particles and will be repaired from line 4.
[0024] 5. The blade is damaged by a foreign object in a limited
area on the leading edge. The damaged area will be cut out along
line 5 and the blade restored along this sectional plane.
[0025] Upon removal of the damaged portion 1a, 2a, 3a, 4a or 5a of
the compressor blade 6 at the respective dotted line 1, 2, 3, 4 or
5, a welding cavity 7 is detachably fitted in a suitable manner to
the bottom side of the essentially horizontally positioned
compressor blade 6 which forms an integral part with the blisk 15.
The mating face 8a of the welding cavity bottom 8 of the welding
cavity 7 which faces the suction side or the pressure side of the
compressor blade 6 is the exact negative of the respective blade
side, while the form of the side walls 9 corresponds to the contour
of the leading edge 10 and/or the trailing edge 11 of the
compressor blade 6. In the example shown in FIG. 2, the tip 12 of
the compressor blade 6, which was subject to normal flow wear, was
separated along line 3 (sectional plane). Upon removal of the blade
portion 3a, the welding cavity 7, whose length corresponds at least
to the length of the blade, is attached temporarily to the
compressor blade 6 and a laser powder welding apparatus 13 for the
generation of a laser beam 13a with separate powder feed nozzle 14
with integrated protective gas supply is brought into position.
Subsequently, with the blade in the horizontal position parallel to
line 3, weld seam after weld seam will be deposited, for example
co-directionally according to FIG. 6. Depending on the respective
thickness of the blade, two or more seams can be deposited on top
of each other on the welding cavity bottom 8. The travels of the
laser optics and the powder feed nozzle are computer-calculated
beforehand on the basis of the missing blade portion determined by
imaging methods in comparison with a master blade, enabling the
welding process to be performed automatically and ensuring a high
quality of the weld. Powder can be input from the side or
circularly if space between the blades permits. Upon completion of
the welding process, the welding cavity 7 is detached and removed
downwards from the compressor blade 6. Subsequently, the compressor
blade 6 is smoothened with electrochemical or cutting methods to
produce the required surface finish. Components other than blades
can be repaired by the present invention.
List of Reference Numerals
[0026] 1 to 5 sectional plane (separation cut or line), at which
the damaged blade portion will be separated and restored,
[0027] 1a to 5a separated (restored) blade portion
[0028] 6 compressor blade
[0029] 7 welding cavity
[0030] 8 welding cavity bottom (backing)
[0031] 8a mating face
[0032] 9 side walls of 7
[0033] 10 leading edge of 6
[0034] 11 trailing edge of 6
[0035] 12 tip of 6
[0036] 13 laser powder welding apparatus
[0037] 13a laser beam
[0038] 14 powder feed nozzle with integrated protective gas
supply
[0039] 15 Blisk
* * * * *